"Have you argued any case before the Supreme Court or the court of appeals?" Session demanded.

Liu said he never argued before the Supreme Court and argued once before a federal appeals court.

Depending on Obama's pick to replace retiring Justice John Paul Stevens, the Liu nomination debate could serve as a template for the partisan fight likely to follow over the next Supreme Court nominee. The Constitution gives presidents the right and responsibility to select men and women for the federal judiciary, and gives senators the right and the authority to approve or reject them.

Committee Chairman Patrick Leahy. D-Vt., on Friday accused Republicans of applying a double standard in Liu's case. He said that in the past he had supported GOP-selected conservative, activist court nominees after they pledged they would be impartial on the bench.

"I hope they will give the same credence to professor Liu's assurances that he understands the proper role of a judge," Leahy said.

"I hope they will keep the same open mind kept by Democratic senators. ... I hope they will not apply a double-standard to this extraordinary nominee," he added.

Liu kept assuring senators his own views would not govern his opinions if confirmed, and would recuse himself from any conflicts of interest.

Asked by Sessions about his criticism of Alito's views on the death penalty, Liu said, "I would have no difficulty or objection of any sort to enforcing the law as written in enforcing the death penalty."

Sessions said before the hearing that Liu's nomination "takes on even greater significance in light of the impending Supreme Court vacancy."

"Senators who say they want judges who are bound to the Constitution will have those statements put to the test. I hope this nomination is not a window into what kind of criteria the president plans to use for the Supreme Court," Sessions said.

Republicans have accumulated numerous Liu quotes in writings and speeches that, they contend, makes him an activist. One of them cited: "The question ... is not how the Constitution would have been applied at the founding, but rather how it should be applied today ... in light of changing needs, conditions and understandings of our society."

Liu would bring added diversity to the appellate courts. There are no Asian-Americans actively serving, although Obama also has nominated U.S. District Judge Denny Chin for the New York-based 2nd U.S. Circuit Court of Appeals.

Liu would serve on the 9th Circuit. The liberal Alliance for Justice said there are 25 judges on that court who were chosen by Democratic presidents, and 22 chosen by Republican presidents.

A Senate hearing for federal appeals court nominee Goodwin Liu quickly erupted into partisan bickering Friday, in a likely test of President Barack Obama's ability to win confirmation for a liberal court pick.
Liu, a University of California, Berkeley law professor,...